Model Railroading > Removing Athearn Flywheels?

I`m repowering an Athearn RTR SD40 with Alliance Loco Works #134 repowering kit. This kit re-uses the stock Athearn flywheels. The Helix Humper motor has bushings on the shaft to increase the diameter from 2mm to 2.4 mm to accept the Athearn flywheels. My problem is, I cannot budge the Athearn flywheels from the Athearn motor. I can`t tell if they`re glued on or just a very tight fit. Has anyone had the same problem or have any suggestions for getting them off. Also, has anyone come out with 2mm diameter flywheels designed for the new Athearn universal system yet. The new Athearn high performance motor is an improvement but they still seem to be current hogs. I was also amazed at the amount of oil they put in the gearboxes when I took it apart. It came spilling out.

grip the motor firmly, and pull the flywheel off. athearn doesn't glue them on. i did this to a few of my locos with no problem. the flywheels are snugly attached to the worm gear. wrap the motor in a towel, and pull try to pull them. the towel will keep you from getting cut on any parts of the motor, and give a better grip. good luck, this is the only way i know of. maybe channel-lock pliers with a firm grip could help.

The 'proper' way to do it would be to use a very small flywheel puller which are sold for model engineers, Walthers probably have something similar.

I have got flywheels off in the past by supporting the flywheel on two bars across a metalworking vise, then very gently starting the shaft into the flywheel with a pin punch.

Alternatively, as it is (probably) a brass flywheel going onto a steel shaft you could use the laws of physics. The brass flywheel will expand more than the steel shaft when warmed up. Warm the flywheel using (eg) a soldering iron or even a cloth soaked in hot water applied only to the flywheel, this may be enough to free the the flywheel to allow it to be withdrawn from the shaft. (Legal Disclaimer: the flywheel may become hot, use caution and take adequate precautions to avoid burning your fingers, dropping the motor on your foot, etc ad nauseum!).

HarrisA Wrote:
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> The 'proper' way to do it would be to use a very
> small flywheel puller which are sold for model
> engineers, Walthers probably have something
> similar.
>
> I have got flywheels off in the past by supporting
> the flywheel on two bars across a metalworking
> vise, then very gently starting the shaft into the
> flywheel with a pin punch.
>
> Alternatively, as it is (probably) a brass
> flywheel going onto a steel shaft you could use
> the laws of physics. The brass flywheel will
> expand more than the steel shaft when warmed up.
> Warm the flywheel using (eg) a soldering iron or
> even a cloth soaked in hot water applied only to
> the flywheel, this may be enough to free the the
> flywheel to allow it to be withdrawn from the
> shaft. (Legal Disclaimer: the flywheel may become
> hot, use caution and take adequate precautions to
> avoid burning your fingers, dropping the motor on
> your foot, etc ad nauseum!).

I came up with the same issue when cleaning one of my Athearn locomotives a few weeks ago. I was able to get the one fly wheel off, but couldn't get the other to loosen. I took the motor apart, exposing the armature. Even then, I couldn't get a good grip to loosen the other fly wheel. So, I took a short strip of masking tape and put it around the flywheel to provide some grip. That worked.

How about putting a small screwdriver blade between the inside end of the flywheel, and the plastic motor housing, and pry it up gently. Have done this off and on for many years and has always worked. When the flywheel starts to move ease upp and it will usually come off easier. NEVER grasp a flywheel with pliers!
dnuck